Fire arrester



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'Gauss REFERENCE SEARCH XR BQLPBBQQFTO A. L.. SMITH 4 Jan. 6, 1970 FIRE ARRESTER Filed Aug. 7, 1967 Mn/i5 A al1-wfg ABSTRACT F DISCLOSURE A fire arrester system for-a blowoff line having v al've means connected to a low spot where liquids collect m a gas pipeline. The arrester` surrounds the end of the blow olf line and mixes atomized low pressure water with the stream from the gas pipeline blowoff line in a suicient ratio to prevent the possibility of fire.

This application discloses method and apparatus for introducing water into a stream from a blowoif line from a gas pipeline to prevent or extinguish fires.

Gas pipelines always contain a number of low spots at which liquids collect. This collection of liquids reduces the effective diameter;` of the pipe and its capacity to deliver gas. It is customgry to place blowoff lines at these low spots. Periodically the valve controlling the blowol line is opened to permit the gas pressure within the line to blow out the accumulated liquids. As with any hydrocarbon stream, there is always danger of fire. This is not'too critical in open i :ountry. However, low spots sometimes occur in highly populated areas and the danger of lire is such that every `arecaution must be exercised to prevent tires at these blow alf lines.

An object of this inventon is to provide a well lire arrester or preventer which will mix atomized lowpressure water with the stream from a gas pipeline blowol line in a sufficient ratio,y to prevent the possibility of lire.

Another object is to proyide a method and apparatus for preventing tire at the outlet of a gas pipeline blowoil line in which the esca-ping high-pressure gas tends to atomize and to draw tlgife low-pressure water from a city system into the escaping gas stream in suicient volume that the gas stream will not support combustion.

Other objects, features and advantages of this invention will be apparent from the drawings, the specification and the claims.

In the drawing:

FIGURE l is a schematic illustration of this invention applied to a pipeline; and,

FIGURE 2 is a view on an enlarged scale of the lire arrester at the top of the blowol pipe.

In practicing the method of this invention, low-pressurewater from a city system is brought to the outlet end of a conventional blow off pipe from a gas pipeline.

. low spot, as represented by the liquid 12. Conventionally,

a blowoff pipe 13 is connected to the low spot 11 and the outlet end of pipe 13 is exposed to atmosphere. By opening the valve 14 in the blowot pipe, the pressure within United States Patent 3,488,171) Patented Jan. 6, 1970 ICC line 10 will drive liquid 12 out through the pipe. In order to prevent the possibility of lire during the blowoff operatioin'a lire arrester indicated generally at 15 is attached tothe blowotf pipe 13 by the conventional pipe vcoupling 16. A water line 17 delivers water from a city system, conventionally about 50 pounds, to the lire arrester 15 through the control valve 18.

lThe arrester may take any form which will atomize the water and throughly mix it with theffescaping stream.

Referring to FIGURE 2, the preferred :arrester includes the pipe 19 which is attached" to a blowotf pipe 13 by the coupling 16. A housing 21 surrounds-pipe 19 4is sealingly secured thereto at its bottom'end as by weld 22. The housing 21 is radially spaced from pipe 19 to provide a distribution chamber 23. Preferably the housing 21 is necked down in anupw'ardly and inwardly frusto-conical manner as shown at 22. The smallest point ofY the necked-down section is approximately equal to the inner diameter of pipe 19. Preferably a plurality of holes 24 are provided in the upper end of pipe 19. This struc-,ture will cause the escaping stream to draw water frokrn'the distribution chamber, atomize the water and mixit with the stream.

vfil/hen it is desired to open the blowol line 13, the valve 18 is first opened to deliver city Water to the distribution chamber 23 so that the water is available about the entire circumference of the upper end of pipe 19. The valve 14 is then opened to permit line pressure 'from the pipeline 10 to blow the accumulated liquids out of the line. As these fluids are blown out of pipe 19, they m-X with the atomized incoming city water in such volurne that the mixture will not support combustion.

In va recent demonstration, a 2inch line was tapped into a pipeline under pressure of 640 to 680 pounds per square inch. The 2inch line had a capacity of llve to six million feet per day under these circumstances. A 100- gallon tank was partially tilled with water, and vplaced under pressure of pounds. The water t'nk was approximately 250 feet away fromI theloutlet of the 2inch line, but the 250-foot line was full of,y water to the 2inch line- The 2inch line was opened arid the escaping gas was ignited. The valve controlling the water line to a ngzzle on top of the 2inch line, of tflle design shown in FIGURE l, was opened. Surprising'lg@ it was found that only about a gallon of water was reqiired to extinguish the llame. In experimentation it was foundv that with the escaping gas ignited, the water valve when cracked and gradually opened would result in the bottom of the fire rising in response to increasing the flow through the water line. As the volume of water was increased, the llame was gradually snuled out. l..

It might be observed that in accordance with this invention`the low-pressure city water and high-pressure pipeline gas are admixed at the outlet of the pipe 19,. They could not be admixed at a point upstream because the pressure of the gas in the blowdown pipe 19 is sufliciently great that it would back up in line 17. In other words, it is only at or immediately adjacentA to the outlet lof pipe 19 that the pressure of the escaping. gap stream is reduced to a point at which it will take on the lowpressure water. As the gas escapes from pipe 19,i it picks up and atomizes the water. The holes 24 tend to load the inner section of the escaping column Qf fluid.

The foregoing disclosure and description of theinvention is illustrative and explanatory thereoli and various changes in the apparatus and method may be made within the scope of the appended claims without departing from the spirit of the invention.

What is claimed is:

1. In a fire arrester system for a gas pipeline:

a blowoff line having valve means therein connected to a low spot in a gas pipeline;

4 t t a cf i..

fire arrester means for atomizing Water comprising:

an inner pipe connected to and forming a continuation ofthe blowoff line; a housing extending circumferentially about the plpe;

and means forming a duid-tight connection between the bottom of the housing and said pipe; said housing spaced radially from said pipe to form a distribution chamber therebetween a'nd extending upwardly beyond the free end of the pipe to provide fluid communication between said chamber and the free end of said pipe about its entire circumference; a low-pressure source of water; j and conduit means having valve means therein con- 1a nectmg the low-pressure source of water to said chamber. a 2. The fire arrester system of claim 1 wherein the housing of the tire-arrester has its upper end necked down to approximately the diameter of said pipe.

References Cited UNITED STATES PATENTS 6/1961 smiul 1an-142 x MORRIS O. WOLK, Primary Examiner R. E; SERWIN, Assistant Examiner U.S. Cl. X.R. 

